Power semiconductor devices are utilized in most modern power applications. For example, power semiconductor devices are used in heating and lighting controls, AC and DC power supplies, and AC and DC motor drives. Power semiconductor devices include, for example, power Metal Oxide Semiconductor Field Effect Transistors (MOSFETs), power Bipolar Junction Transistors (BJTs), and power thyristors. Power semiconductor devices can be formed in various material systems. However, Silicon Carbide (SiC) power semiconductor devices such as those manufactured and sold by Cree, Inc. are particularly beneficial due to their superior performance. For example, SiC power semiconductor devices have lower specific on-resistance and faster switching than Silicon (Si) power semiconductor devices for the same breakdown voltage, higher current densities than Si power semiconductor devices, and higher temperature of operation than Si power semiconductor devices.
Typically, a power semiconductor device is a vertical device fabricated on a semiconductor die. The semiconductor die for the power semiconductor device includes an active area and a control contact area. The active area is an area of the semiconductor die in which active features (e.g., source and channel regions) of the power semiconductor device are fabricated. The control contact area is a non-active area of the semiconductor die used to provide electrical connection between a corresponding control bond pad and control regions (e.g., channel, gate, or base regions) of the power semiconductor device in the active region of the semiconductor die. During operation, the active region carries a large amount of current (e.g., 1 Amp (A), 5 A, 10 A, 20 A, 50 A, or higher); however, the control contact area carries only a small amount of current. As such, in order to maintain current density at an acceptable level, the active area is typically much larger than the control contact area. For a vertical power semiconductor device, a current rating of the power semiconductor device is proportional to a size of the active area of the semiconductor die. Thus, for a 2× increase in the rated current of the power semiconductor device, there is a 2× increase in the size of the active region.
In order to connect the power semiconductor device to an external package, bond pads are formed on the semiconductor die. Using a power MOSFET as an example, a source bond pad is typically formed over the active area of the semiconductor die. The source bond pad is electrically connected to source regions within the active area of the semiconductor die. In addition, a gate bond pad is formed over the control contact area. The gate bond pad is electrically connected to channel regions within the active area of the semiconductor die. Lastly, for a vertical power MOSFET, a drain bond pad is formed on a bottom surface of the semiconductor die. During packaging, the bond pads are electrically connected to a package. In particular, the source and gate bond pads are typically connected to the package via corresponding wire bonds.
As power semiconductor devices evolve, there is increasing demand to decrease the size of the semiconductor die and thus the cost of the power semiconductor devices. As such, there is a need for systems and methods for reducing the size of the semiconductor die for power semiconductor devices.